The present invention relates to a variable displacement swash plate type compressor.
Such a variable displacement swash plate type compressor is disclosed in Japanese Laid-Open Patent Publication No. 52-131204. This compressor includes a movable body that moves along the axis of a rotary shaft to change the inclination angle of a swash plate. A control pressure chamber is formed in the housing. As control gas is introduced to the control pressure chamber, the pressure inside the control pressure chamber is changed. This allows the movable body to move along the axis of the rotary shaft. As the movable body is moved along the axis of the rotary shaft, the movable body applies to a central portion of the swash plate a force that changes the inclination angle of the swash plate. Accordingly, the inclination of the swash plate is changed.
In the configuration in which a movable body applies a force that changes the inclination angle of a swash plate to a central portion of the swash plate as in the compressor of the above described publication, a great force is required for changing the inclination angle of the swash plate. In this regard, for example, it may be configured such that a movable body applies a force that changes the inclination angle of a swash plate to a peripheral portion of the swash plate. In this case, compared to the case in which a movable body applies a force for changing the swash plate inclination angle to the central portion of the swash plate, the inclination angle can be changed by a small force. This reduces the flow rate of control gas that needs to be introduced to a control pressure chamber to change the inclination angle of the swash plate.
However, in the configuration in which the movable body applies a force for changing the inclination angle of the swash plate to the peripheral portion of the swash plate, a change in the inclination angle of the swash plate causes the movable body to receive a moment that acts to tilt the movable body with respect to the moving direction. If the movable body tilts with respect to the moving direction, a force that supports the tilting motion of the movable body is generated between the movable body and the rotary shaft while the movable body and the rotary shaft are contacting each other at two contact points on the opposite sides of the rotary shaft. The friction caused by the force generates a twist between the movable body and the rotary shaft. The twist increases the sliding resistance, hindering smooth movement of the movable body along the axis of the rotary shaft. This hampers smooth change in the inclination angle of the swash plate.